Christopher R. Graber, MD Salina Women’s Clinic 7 May 2010

Overview Background Normal Labor Friedman curve Abnormal Labor (dystocia) Risk factors for dystocia Complications from dystocia Augmentation Other

Background Labor – uterine contractions of sufficient intensity, frequency, and duration to cause cervical effacement and dilation A retrospective diagnosis Latent vs. active Dystocia – slow, abnormal progression of labor Leading indication for C/S Responsible for 60% of all C/S

Normal Labor Contractions  dilation  delivery First stage – dilation up to 10cm Latent  active Second stage – from 10cm to delivery Third stage – del baby to del placenta Fourth stage – until 6w postpartum Friedman curve Developed in 1950’s, challenged recently

Normal Labor First Stage (minimum; Friedman) Nulliparas – 1.2 cm dilation/hr Multiparas – 1.5 cm dilation/hr First Stage (Alexander, 2002) Epidural slows active phase by 1hr Second Stage (median; Kilpatrick, 1989) Nulliparas – 50 min Multiparas – 20 min

Abnormal Labor Anything not normal Power, passenger, passage CPD, failure to progress, dystocia Arrest of dilation vs. Arrest of descent Protraction Second stage arrest/prolongation Nullip – 2h (3h w/ epidural) Multip – 1h (2h w/ epidural)

Risks for Dystocia Maternal age Medical complications of pregnancy Diabetes, hypertension, PROM Chorio, macrosomia, pelvic contractions Second stage Nulliparity, epidural analgesia, OP, long first stage

Complications from Dystocia Chorioamnionitis Fetal infection and bacteremia Pelvic floor injuries? Pressure necrosis  fistula formation Increased risk of operative delivery

Augmentation Consider oxytocin for protraction or arrest Goal: 3-5 ctx in 10min, >200 Montevideo units “2-hour rule” should likely be 4-6 hours If second stage arrest Continued observation (continued augmentation) Operative vaginal delivery Cesarean delivery Low-dose vs. high-dose oxytocin

Other No clear role for pelvimetry in prediction of dystocia Walking during labor doesn’t hurt or help Continuous support during labor is encouraged Amniotomy may enhance progress of active labor but increases risk of fever Women with twins may have augmentation

Induction and Augmentation (by me) Bishop score to determine if cervical ripening is needed Cervidil (dinoprostone) vs cytotec (misoprostol) Pitocin – start at 2mu/min Increase by 2mu every 15 minutes Maximum 40mu/min Tips If reach 40 and no Δ, off for 30 min then restart 20 Consider (re-)prostaglandin

References ACOG practice bulletin 49 Dystocia and Augmentation of Labor ACOG practice bulletin 10 Induction of Labor